Which image formats does Image Crusher support?

Image Crusher supports PNG, JPEG, WebP, GIF, and BMP. PNG, GIF and BMP are compressed using median-cut colour quantization and optional dithering. JPEG and WebP use a quality slider that controls the browser's native lossy codec.

How much can Image Crusher reduce my file size?

PNG reductions typically range from 40% to 80% depending on colour depth settings. JPEG and WebP reductions depend on quality — a quality of 75 usually saves 40–60% with minimal visible loss.

Can I compress multiple files at once?

Yes. Image Crusher supports batch processing. Drag and drop or select multiple files, configure your settings once, and compress them all in one go. Download files individually or as a ZIP.

Compress Images Online Free — PNG, JPEG, WebP, GIF, BMP

🗜️

Drop images here

PNG · JPEG · WebP · GIF · BMP · supports multiple files · max 50MB each

Compression Settings

No file loaded

Colour Reduction

Dithering

Strip alpha channel

Quality

80%

Higher = better quality, larger file. 75–85 is the usual sweet spot.

Scale Down

50%

Original Compressed

All Files

Filename	Savings	Action

Free Online Image Compressor

Image Crusher is a free, privacy-first compression tool that shrinks image files directly in your browser. It supports PNG, JPEG, WebP, GIF, and BMP. Unlike server-based compressors, every byte stays on your device — Image Crusher is ideal for sensitive screenshots, proprietary artwork, and confidential documents.

PNG, GIF and BMP — Palette Compression

For PNG, GIF, and BMP files, Image Crusher uses median-cut colour quantization to convert 32-bit truecolour images into indexed-colour images with as few as 16 colours. This typically achieves 40–80% size reduction. Three dithering modes let you control the visual trade-off: Floyd-Steinberg error-diffusion produces smooth gradients, ordered (Bayer matrix) dithering gives a fast patterned look, and no-dither mode is ideal for flat-colour graphics and logos. Note that GIF and BMP are re-encoded as PNG, which is both smaller and more widely supported.

JPEG and WebP — Quality Compression

For JPEG and WebP, Image Crusher uses the browser's native codec directly via a quality slider (10–100). A quality of 75–85 typically reduces file size by 40–60% with minimal perceptible quality loss. Lower values produce smaller files at the cost of visible artefacts. The output format matches the input — JPEG in, JPEG out; WebP in, WebP out.

Batch Compression

Drag and drop an entire folder of mixed image types, configure your settings once, and compress them all in a single pass. A detailed results table shows savings per file. You can download files individually or as a ZIP archive.

Before-and-After Comparison

Every compressed image gets a live side-by-side comparison slider so you can inspect quality before downloading. Drag the handle left and right to compare the original against the compressed version at pixel level.

Frequently Asked Questions

Which image formats are supported?

PNG, JPEG, WebP, GIF and BMP. PNG, GIF and BMP are compressed with palette quantization and output as PNG. JPEG and WebP use a quality slider and keep their original format.

Are my images uploaded to a server?

No. Image Crusher runs 100% client-side using JavaScript. Your images are processed in your browser's memory and never leave your device.

How much smaller will my files be?

PNG reductions are typically 40–80% depending on colour depth. JPEG and WebP reductions depend on quality — around 75 usually saves 40–60% with minimal visible loss. GIF and BMP converted to PNG are often dramatically smaller regardless of quantization settings.

Why is my GIF output a PNG?

Web browsers cannot encode GIF files via the canvas API. Image Crusher quantizes GIF frames and re-encodes them as PNG, which is lossless, widely supported, and typically smaller than the original GIF.